This happens to me randomly, and then it'll fix itself after 2-3 minutes, the internet access will last for 5 minutes, then repeat the process for hours, it'll fix itself randomly for a few hours, and then begin again... It pisses me off.

I've had that problem for a while, and first I thought it was a Linux Mint problem and reinstalled it and all but it didn't solve it. I googled it a bit and found something about the ISP giving less speed at certain times or the network being just too full.